This invention relates to a lubricating system for a vertical shaft engine and more particularly to an improved lubricating system for use with a walk-behind lawn mower or similar implement.
In a large number of applications, an internal combustion engine is operated with its output shaft extending in a vertical direction. Examples of such applications are found in rotary lawn mowers wherein the grass is cut by a cutting blade that rotates about a vertically extending axis and is driven by an engine having its output shaft similarly disposed. Such an arrangement offers considerable utility because the engine output shaft can be directly coupled to the cutting blade shaft without the necessity of intervening transmissions or gear reduction units. When such an arrangement is employed, the output shaft passes through the center of the engine crankshaft. This presents certain problems in connection with the lubrication of the engine, particularly when the engine has a splash-type lubrication system.
Specifically, this type of orientation results in a crankcase that has relatively shallow height and a large cross-sectional area in a horizontally extending plane. As such, the depth of the lubricant in the crankcase can differ significantly when the engine is in motion and the "sloshing" of the lubricant can result in inadequate lubrication under these conditions.
It is, therefore, a principle object of this invention to provide an improved vertical shaft engine and lubricating system for such an engine.
It is another object of this invention to provide an improved arrangement for lubricating a vertical shaft engine.
It is yet a further object of this invention to provide an improved lubricating system for a vertical shaft engine wherein a splash-type lubrication system is employed.
In connection with splash lubricated internal combustion engines, it has been proposed to employ an oil slinger which is driven from the engine output shaft or an engine accessory shaft and which dips into the lubricant into the crankcase and throws it onto certain components of the engine to be lubricated. Although such an arrangement is effective in insuring adequate lubrication of all components of the engine with a splash-type system, there are certain disadvantages. First of all, the motion of the engine can cause the slinger to be immersed at different levels in the lubricant and the spray pattern will differ depending upon the degree of immersion. Furthermore, the operation of the slinger in the crankcase can tend to cause foaming of the lubricant in the crankcase that can adversely affect the lubrication of other components in the engine.
It is, therefore, a still further object of this invention to provide an improved a splash lubricating system of the type employing an oil slinger.
It is a yet further object of this invention to provide a baffling arrangement for an oil slinger that will control the direction of flow of the oil and will minimize the frothing of the oil in the crankcase.